A multi-input/multi-output matrix switch is used to, for example, switch signal paths at nodes in a network. A conventional n-input/n-output switch comprises n 1-input/n-output switches, n n-input/1-output switches, and n2 connection means for connecting the switches to each other. Reference 1 (Japanese Patent Laid-Open No. 9-9312) discloses an example of such an n-input/n-output switch. The n-input/n-output switch disclosed in reference 1 has an arrangement which can be applied as a cross-connect switch which can output input signals from n input terminals 1011 to 101n in all combinations to n output terminals 1021 to 102n, as shown in FIG. 19. This arrangement will be described in more detail below by exemplifying the case of n=4.
As shown in FIG. 20, a conventional 4-input/4-output switch (4×4 switch) includes eight Single-Pole 4-Throw (SP4T) switches 1031 to 1038 in correspondence with input terminals 1011 to 1014 and output terminals 1021 to 1024. The SP4T switches 1031 to 1038 are bidirectional switches, each functioning both as an 1-input/4-output switch and a 4-input/1-output switch.
Each of the SP4T switches 1031 to 1038 includes one common terminal and four individual terminals. Sixteen interconnection transmission lines 10411 to 10444 connect the individual terminals of the SP4T switches 1031 to 1034 on the input side to the individual terminals of the SP4T switches 1035 to 1038 on the output side. Each of the SP4T switches 1031 to 1038 is designed such that the common terminal connects to one of the four individual terminals (does not connect to the remaining three terminals). These switches are controlled as a whole such that the four input terminals 1011 to 1014 one-to-one connect to the four output terminals 1021 to 1024. Referring to FIG. 20, the symbol “◯” with a satin-like pattern indicates an interconnection intersection 116 where two transmission lines intersect each other but do not electrically connect to each other.